Telephony.



E. R. GORWIN;

TELEPHONY.

APPLICATION FILED APR.24,'1911.

Patented Feb. 25, 1913.

Jaye/2307',

Cozzua'm UNITED STAT IP ATENT oEEioE.

EL u R n. oonwm, or dHIoAGo, ILLINOIS, sssrenon T0 oonwm TELEPHONE MANUFACTURING COMPANY, A CORPORATION or ILLINOIS.

TELEPHONY.

To all whom it may concern,

Be' it known that I, ELMER R. (3 mm, citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented, a certain new and useful Improvement in Telephony, of which the following is a full, clear, concise,-"-and exact description, reference being had to the accompanying drawings, forming a party of this specification.

My invention relates, to telephone lexchange systems and has for one of its objects the provision of improved "means whereby 'one telephone line may be employed to connect any one of a plurality of stations common thereto with another telephone line in such a manner as to preventthe connection of telephonic apparatus at another of said stations with thetelephone line when previously taken for use; -,This feature of my invention maybe practised in connection with a telephone line that-e'xftends to an exchange though I do not-fwish to be limited to this embodiment'of the invention.

My invention in another of its aspects re lates to that .class of telephone exchange systems in which selecting mechanism is employed at the exchange for effecting an extension of the telephone line and this feature of my invention may be embodied in an automatic telephone exchange system thou li it is not to be limited to systems in Which t ecalled parties are automatically connected with calling parties asit is'of service where link circuits atthe exchangearexautomati cally selected to constitute telephone line continuations.

By means of the present feature of my invention a plurality of stations may beassociated with the same telephone line associated with selecting mechanism at an exchange and such telephone line may be limited to operative association with the selecting mechan m governing means at any station first ,lazr nriating the line so that any other statkm or stations appropriating the line cannot interfere with the operation of the selecting mechanism. I

I will explain my invention mercifully by reference to the accompanying drawing showing one embodiment thereof, in which a telephone line extends from an automatic exchange to a plurality of substations that are here indicated as being in permanent as Specification {Jr Letters Patent," t t F 25, 191 Application filedcApri l 24,:1911. Serialflo 822,941.

soeiation with the line so as'to constitute said line" a party telephone line ,or in other words soas to constitute a portion of said line extending from the station nearest the exch'ange'to the other station an extension line, though it is to be understood that I do lineequipment. V y

I do not deem it necessary to describe the automatic telephone exchange system to -which the line 11 extends as such automatic systems are well known to those skilled in the art. It is known that a bridge connection normally exists between the sides of the telephone line 11 or, the extensions of said sides and which bridge connection includesthe battery 2 and an impedance 8, this bridge connection and the battery therein' includedtaking part in the operation of the equipment of my invention. A third conductor 4 extends from a midpoint of this bridge to the substations A B that are connec'tedwith the automatic exchange by the talkingfsides,11 of the telepho e line. An el'ectro-magnet or relay5 is pro ded at each of the substations, the left hand armature .switchof each relay taking part in establishing the -connection of the telephone receiver G'andtranSmitter 7 with the telephone line when such relay is inert, each telephone receiver and transmitter being included in a complete bridge between the sides of the telephone line when the receiver is removed from its switch-hook 8.

Assuming that the station B desires automatically to effect an extension of the telephone line 1, as for example, by automatition with the line 11 through the intermediation, of automatic telephone exchange equipment, the party at station B will remove his' receiver from its switch-hook and thereby establish a bridge across the'line which not only includes the receiver and transmitter but also includes a circuit in-v terrupting means 9, such as the well known dial, whereby the party at'station B is enabled to effect the desired extension of the has removed his receiver from\its switchhook the line 1 is ciation with the circuit interrupting means 9 at any other station since the party at suchother station, in endeavorin to a propriate the line 1, will complete t e esta vnot limit myself to such a party or'extension cally bringing a line to be called in connec-v line 1. The moment the party at station B" arded from circuitassolishment ,of an initial energizing circuit through his relay by reason of the momen tary simultaneous engagement of the switchhoolr 8 withits lower contact which is a followup contact and the contact next above the switch-hook, thebalance of this circuit through the left hand winding of the relay 5 at station A being completed owing to the inertcondition of the relay 5 at the station B. The circuit established by the rising switch-hook S at station A and the inert rcla-y 5 at station B is traceable from the upper pole of the battery 2 through the lefthand windingo'f'the relay 5 at station A, the switch-hoolt and the two contacts between which it is disposed, the upper side of the line 1, the contacts 10 and 11 at station B, the left hand armature switch of the relay 5 and its normal contact, the circuit interrupter 9 at station B, the telephone receiver and transmitter at station B, the right hand arn'iatureswitch at station B to the lower pole, of the battery 2. A local holding circuit is immediately established through the relay 5 at station A which may be traced from the upper pole of the battery 12, the two uppermost switch-hook contacts 13, the left hand armature switch of relay 5 at station A and the alternate con tact of such switch, the elements 6, 7 and 9 at station A, the right hand armature switch of relay 5 at station'A, the lower of the two alternate contacts of sucharmature switch to the battery 12. The right hand armature switch being thus removed from its normal contact opens the circuit througl'i' equipment at station A may be restored to' normal when the party thereat restores his receiver upon its switclrhook owing to the fact that the only circuit remaining intact for the relay 5 at station A is thereupon broken at the contacts 13. When the party at station A thus seeks connection with the appropriated line 1 a test manifestation is produced in his telephone receiver due to the establishment of a test circuit that maybe traced from the upper terminal of the battery 12 through the contacts 13 atstation A, the left hand armature switch of relay 5 and its alternate contact at station A, the elements 6, 7 and 9 at station A, the right hand armature switch of relay 5 at station a and the upset alternate contact of such armature switch and the interrupter 14 that produces the characteristic testing current,

I will not therefore specifically describe the.

similar results that occur when the party at station A appropriates the ,line 1 and the party at station E seeks the use of such line after its appropriation.

As the system is illustrated the station A constitutes the main substation of the line, a bell 15 being located in bridge of the line and in series with a condenser 16 whereby such station A may be signaled from the exchange or by an automatic subscriber in the event of the system being a pure auto matic telephone exchange system, If the party wanted should be at station E instead of: at station A then the party at station A may close circuit through the signal 17 at station E by the manipulation of the but ton 18.

lVhile I have herein shown and particularly described the preferred embodiment of my intention, I do not wish to be limited to the precise construction shown as changes may be made without departing from the spirit of my invention. but

Having thus described my invention 1 claim as new and desire to secure by Letters Patent the "following:

1. A telephone system having telephone stations on the same telephone line; electromagnetic mechanism at one station serving when inert to take part in connecting the telephone at the same station therewith with the line: switching mechanisms at the station for apwtmriating the line and jointly cooperation 2:: establishing the energizing circuit for Milli electro-magnetic mechanism when both are operated in the effort to appropriate the line; and a locking circuit for said electro-magnetic mechanism established by said electro-magnetic mechanism when energized, said locking circuit being under the control of the switching mechanism at the same stationtherewith so as to be opened when said switching mechanism is restored to normal. 1

2. A telephone system having telephone stations on the same telephone line; electromagnetic mechanism at one station serving when inert to take part in connecting the telephone at the same station therewith with the line; switching mechanisms at the stations for appropriating the line and jointly cotlperating in establishing the energizing circuit for said electr c-magnetic mechanism when both are operated in the eii'ort to appropriate the line; and a locking circuit for said electro-magnetic mechanism established by said electro-magnetic mechanism when energized, said locking circuit being under the control of the switching mechanism at the same station therewith so as to be opened when said switching mechanism is restored to normal, the electro-magnetic mechanism having one COll in its energizing clrcuit and another coil in its locking circuit.

' nism at one station serving when inert to.

3. A telephone system having telephone stations on the same telephone line and which line extends to anexchange; automatically operated selecting mechanism at the exchange for effecting an extension of said telephone line; electr c-magnetic mechaand line circuit interrupting mechanism in "circuit with the telephone line'independently of the locking circuit whereby the line circuit maybe interrupted without disturb magnetic mechanism. a v 4. A- telephone system having telephone stations'onthe same telephone line and, which line extends to an exchange auto,'

matically operated selecting mechanism' at the" exchange for effecting an extension of? end telephone line; electro-magnetic mechaat one station serving when inert to the telephone at the the line gswitching mechanism'sat the stations forappro V priatm take part in connecting came stationthe'rewith with the line and jointly cooperating in establis ing-the energizing circuit for said electro-magnetic mechanism when both are operated in theeffort to appropriate the line; a locking circuit for said electro-magnetic mechanism established bysaid electromagnetic mechanism when energized, said locking circuit being under the control of the sw tching mechanism at the same station therewith so as to be 'opened when said switching mechanism ;is restored-to normal, the electro-magnetic mechanism having one coil in its energizing circuit and another coil in itslocking circuit; and line circuit interrupting'mechanism in circuit with the tele-- phone line independently of the locking circuit whereby the line circuit may be interrupted without disturbing the locking condition of the electro-magnetic mechanism.

5. A telephone system having telephone stations on the same telephone line; electromagnetic mechanism at one station serving when inert to take part in connecting the telephone at the samestation therewith with switching mechanism the elect-ro-magnetic mechanism having one- .coil 1n 1ts energized c rcuit-and another coil the line; 'switchingm'echanis ms at the sta- I tions each. including a telephone receiver supporting switch hook for operating and provided at each station for appropriating the line, in establishing the energizing circuit for said switches jointly coiiperating said electro-magnetic mechanism when both are operated in the effort to appropriate the line; and a locking circuit for said electro magnetic mechanism established by said electro-magn tic mechanism when energized said locking circuit being under the control of the switching mechanism at the same sta tion therewith so as to be opened when said switching mechanism is restored to normal.

6. A telephone system having telephone stations on the same telephone line; electrotelephone at the-samestation therewith with the line; switching mechanisms at the statio'ns each including a telephone receiver supporting switch hook-for operating it and provided at, each station for appropriating the line, said switches jointly cotiperating in establishing the energizing circuit for said electro-magnetic mechanism when both are operated'in the, effort to appropi'iate the ,1 line; and a locking'circuitfor said electro- Qmg thealocln'ng condition of theelectromagnetic mechanism established by said of the switching mechanism at the same station therewith so as -.totbe-opened when said is restored tonormal,

in its lockingcircuit.

stations on the same telephone line and, which-line extends'to an exchange;'a1itomatically operated selecting mechanism at the exchange for efiecting an extension of said telephone line; electro-inagne tic mechanism at one station serving when inert to --.magnetic mechanism at one station serving: -wheninert to take part 111 connecting the el -ectro-magnetic mechanism when energized, said l'ockmg circuitibelng under the control *3 fl '7. A telephone system having telephone a take part in connecting the telephone at the samestation therewith with the line; switching mechanisms at the stations each including a telephone receiver supporting switch hook for operating it and provided at each station for appropriating the line, said switches jointly cotiperat-ing in establishing the energizing circuit for said'elect'ro-magnetic mechanism when both are operated in the effort to appropriate the line; a locking circuit for said said locking circuit being under the controlmechanism at the same station therewith so as to be opened when said switching mechanism is restored to normal; and/line circuitzo' electromagnetic mechanism established by said electromagnetic mechavnism when energized,

of the switching i said telephone line; electromagnetic mechanism at one station serving when inert to take part in connecting the telephone at the.

same station therewith with the line; switching mechanisms at the stations each includ ing atelephone receiver supporting switch hook for operating it and provided at each station for appropriating the line said switches jointly cooperating in establishing the energizing circuit for said eleCtro-magnetic mechanism when both are operated in theeliort to appropriate the line; a locking circult for said electro-magnet mechanism established by said electro-magnetic mecha- Copiesof this patent may be obtained for Loci-ave nism when energized, said locking circuit being under the control of the switchlng mechanism at the samestation therewith so as to be opened when said switchlng mechanism is restored to normal, the electro-magnetic mechanism having one coil in its ener- :gizing circuit and another coil in its locking circuit; and line circuit interrupting mechanism in circuit with the telephone line independently of the locking circuit, whereby the line circuit may be interrupted without disturbing the locking condition of the electro-magnetic mechanism. I

In witness whereof, I hereunto subscribe my name this twenty third day of March A. D.,' 19l1.

ELMER R. CORWIN.

Witnesses G. L. CnAec, ETTA LLVVHITE.

five cents each, by addressing the Commissioner of Patents, Washington, D. 0. 

